638580721848 has 16 divisors (see below), whose sum is σ = 1596451804680. Its totient is φ = 212860240608.

The previous prime is 638580721847. The next prime is 638580721949. The reversal of 638580721848 is 848127085836.

It is a junction number, because it is equal to n+sod(n) for n = 638580721791 and 638580721800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638580721847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13303765015 + ... + 13303765062.

Almost surely, 2^638580721848 is an apocalyptic number.

It is an amenable number.

638580721848 is an abundant number, since it is smaller than the sum of its proper divisors (957871082832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638580721848 is a wasteful number, since it uses less digits than its factorization.

638580721848 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26607530086 (or 26607530082 counting only the distinct ones).

The product of its (nonzero) digits is 20643840, while the sum is 60.

The spelling of 638580721848 in words is "six hundred thirty-eight billion, five hundred eighty million, seven hundred twenty-one thousand, eight hundred forty-eight".